This invention relates to a process for the hydrogenation of nitriles and dinitriles to the corresponding primary amines in the presence of a supported cobalt and/or nickel catalyst, wherein the support is an oxide of aluminum, silicon, titanium, iron, or a mixture thereof.
The catalytic hydrogenation of nitriles and dinitriles in the presence of ammonia is perferably carried out with the use of solid-bed catalysts obtained by the precipitation, on porous supports, or thermally decomposable cobalt salts and/or nickel salts in combination with other metallic salts which decompose on heating to difficultly reducible oxides, e.g., salts of chromium and manganese. Silica gel, silicic acid, aluminum silicates, pumice and aluminum oxides have been suggested as suitable supports for these catalysts (German Pat. No. 964,864). Using such supported catalysts, the hydrogenation of nitriles and dinitriles usually can be conducted at about 100.degree. C. under a pressure of 150-300 atmospheres in the presence of ammonia and hydrogen. Optionally, the reaction can be conducted in an inert solvent in order to obtain advantageous removal of the heat of reaction.
These conventional catalysts have an inadequate hydrogenation lifetime. Especially when employed in the presence of diluents, the catalyst bed is clogged up, within a relatively short reaction time, so that the catalyst must be replaced.
It is an object of this invention to provide a hydrogenation process employing supported hydrogenation catalysts which have a longer lifetime. Other objects will be apparent to those skilled in the art to which this invention pertains.